You know, I hadn't watched this scene in so long, I had to watch it again after seeing your comment just to make sure. I still say the cum is fake. There are some key signs. The camera pans away while he is "cumming". There's a wide shot with no evidence of any cum, even though in sequence it is AFTER he has cum, and the part of her body where he came is clearly shown. Then they go in for a close shot, and the cum suddenly magically appears. And it's still shown there from that point on, even after the camera pans away again. Some pretty clear signs of a fake cum shot, if you know what to look for.